/*
 * Copyright (C) 2011 Alex Kuiper <http://www.nightwhistler.net>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.nightwhistler.htmlspanner.handlers;

import java.util.ArrayList;
import java.util.List;

import android.graphics.*;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.shapes.RectShape;
import android.util.Log;
import net.nightwhistler.htmlspanner.SpanStack;
import net.nightwhistler.htmlspanner.TagNodeHandler;

import org.htmlcleaner.ContentNode;
import org.htmlcleaner.TagNode;

import android.graphics.Paint.Style;
import android.graphics.drawable.Drawable;
import android.text.Layout.Alignment;
import android.text.Spannable;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.text.style.AlignmentSpan;
import android.text.style.ImageSpan;

/**
 * Handles simple HTML tables.
 * 
 * Since it renders these tables itself, it needs to know things like font size
 * and text colour to use.
 * 
 * @author Alex Kuiper
 * 
 */
public class TableHandler extends TagNodeHandler {

	private int tableWidth = 400;
	private Typeface typeFace = Typeface.DEFAULT;
	private float textSize = 16f;
	private int textColor = Color.BLACK;

	private static final int PADDING = 5;

	/**
	 * Sets how wide the table should be.
	 * 
	 * @param tableWidth
	 */
	public void setTableWidth(int tableWidth) {
		this.tableWidth = tableWidth;
	}

	/**
	 * Sets the text colour to use.
	 * 
	 * Default is black.
	 * 
	 * @param textColor
	 */
	public void setTextColor(int textColor) {
		this.textColor = textColor;
	}

	/**
	 * Sets the font size to use.
	 * 
	 * Default is 16f.
	 * 
	 * @param textSize
	 */
	public void setTextSize(float textSize) {
		this.textSize = textSize;
	}

	/**
	 * Sets the TypeFace to use.
	 * 
	 * Default is Typeface.DEFAULT
	 * 
	 * @param typeFace
	 */
	public void setTypeFace(Typeface typeFace) {
		this.typeFace = typeFace;
	}

	@Override
	public boolean rendersContent() {
		return true;
	}

    private void readNode(Object node, Table table) {

        // We can't handle plain content nodes within the table.
        if ( node instanceof TagNode ) {

            TagNode tagNode = (TagNode) node;

            if (tagNode.getName().equals("td")) {
                Spanned result = this.getSpanner().fromTagNode(tagNode, null);
                table.addCell(result);
                return;
            }

            if (tagNode.getName().equals("tr")) {
                table.addRow();
            }

            for (Object child : tagNode.getAllChildren()) {
                readNode(child, table);
            }
        }

    }

	private Table getTable(TagNode node) {

        String border = node.getAttributeByName("border");

        boolean drawBorder = !"0".equals(border);

		Table result = new Table(drawBorder);

		readNode(node, result);

		return result;
	}

	private TextPaint getTextPaint() {
		TextPaint textPaint = new TextPaint();
		textPaint.setColor(this.textColor);
        textPaint.linkColor = this.textColor;
		textPaint.setAntiAlias(true);
		textPaint.setTextSize(this.textSize);
		textPaint.setTypeface(this.typeFace);

		return textPaint;
	}

	private int calculateRowHeight(List<Spanned> row) {

		if (row.size() == 0) {
			return 0;
		}

		TextPaint textPaint = getTextPaint();

		int columnWidth = tableWidth / row.size();

		int rowHeight = 0;

		for (Spanned cell : row) {

			StaticLayout layout = new StaticLayout(cell, textPaint, columnWidth
					- 2 * PADDING, Alignment.ALIGN_NORMAL, 1f, 0f, true);

			if (layout.getHeight() > rowHeight) {
				rowHeight = layout.getHeight();
			}
		}

		return rowHeight;
	}

	@Override
	public void handleTagNode(TagNode node, SpannableStringBuilder builder,
			int start, int end, SpanStack spanStack) {

		Table table = getTable(node);

		for (int i = 0; i < table.getRows().size(); i++) {

			List<Spanned> row = table.getRows().get(i);
			builder.append("\uFFFC");

			TableRowDrawable drawable = new TableRowDrawable(row, table.isDrawBorder());
			drawable.setBounds(0, 0, drawable.getIntrinsicWidth(),
					drawable.getIntrinsicHeight());

			spanStack.pushSpan(new ImageSpan(drawable), start + i, builder.length());

		}

        /*
         We add an empty last row to work around a rendering issue where
         the last row would appear detached.
         */
        builder.append("\uFFFC");
        Drawable drawable = new TableRowDrawable(new ArrayList<Spanned>(), table.isDrawBorder());
        drawable.setBounds(0, 0, tableWidth, 1);
        builder.setSpan(new ImageSpan(drawable), builder.length() -1, builder.length(),
                Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

        /*
         Center the entire table
         */
        builder.setSpan(new AlignmentSpan() {
            @Override
            public Alignment getAlignment() {
                return Alignment.ALIGN_CENTER;
            }
        }, start, builder.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

        builder.append("\n");
	}

	/**
	 * Drawable of the table, which does the actual rendering.
	 * 
	 * @author Alex Kuiper.
	 * 
	 */
	private class TableRowDrawable extends Drawable {

		private List<Spanned> tableRow;

        private int rowHeight;
        private boolean paintBorder;

		public TableRowDrawable(List<Spanned> tableRow, boolean paintBorder) {
			this.tableRow = tableRow;
            this.rowHeight = calculateRowHeight(tableRow);
            this.paintBorder = paintBorder;
		}

		@Override
		public void draw(Canvas canvas) {
			Paint paint = new Paint();
			paint.setColor(textColor);
			paint.setStyle(Style.STROKE);

			int numberOfColumns = tableRow.size();

			if (numberOfColumns == 0) {
				return;
			}

			int columnWidth = tableWidth / numberOfColumns;

			int offset = 0;

			for (int i = 0; i < numberOfColumns; i++) {

				offset = i * columnWidth;

                if ( paintBorder ) {
				    // The rect is open at the bottom, so there's a single line
				    // between rows.
				    canvas.drawRect(offset, 0, offset + columnWidth, rowHeight,
						paint);
                }

				StaticLayout layout = new StaticLayout(tableRow.get(i),
						getTextPaint(), (columnWidth - 2 * PADDING),
						Alignment.ALIGN_NORMAL, 1f, 0f, true);

				canvas.translate(offset + PADDING, 0);
				layout.draw(canvas);
				canvas.translate(-1 * (offset + PADDING), 0);

			}
		}

		@Override
		public int getIntrinsicHeight() {
			return rowHeight;
		}

		@Override
		public int getIntrinsicWidth() {
			return tableWidth;
		}

		@Override
		public int getOpacity() {
			return PixelFormat.OPAQUE;
		}

		@Override
		public void setAlpha(int alpha) {

		}

		@Override
		public void setColorFilter(ColorFilter cf) {

		}
	}

	private class Table {

        private boolean drawBorder;
        private List<List<Spanned>> content = new ArrayList<List<Spanned>>();

        private Table( boolean drawBorder ) {
            this.drawBorder = drawBorder;
        }

        public boolean isDrawBorder() {
            return drawBorder;
        }

		public void addRow() {
			content.add(new ArrayList<Spanned>());
		}

		public List<Spanned> getBottomRow() {
			return content.get(content.size() - 1);
		}

		public List<List<Spanned>> getRows() {
			return content;
		}

		public void addCell(Spanned text) {
			if (content.isEmpty()) {
				throw new IllegalStateException("No rows added yet");
			}

			getBottomRow().add(text);
		}
	}

}
